The present invention relates to tuners, and relates more particularly to a cable television (CATV) tuner which uses a tracking filter and a MMIC (microwave monolithic integrated circuit) to amplify and change the radio frequency signal of the cable television into an intermediate frequency signal, an inband and outband matching network to eliminate composite triple beat so as to provide a satisfactory intermediate frequency signal or channel signal.
During the transmission of a cable television radio frequency signal, the video signal and audio signal are converted into a RF (radio frequency) signal by a high power radio frequency modulator, and then the modulated radio frequency signal is sent through the program channel to the subscribers. As the bandwidth of the channel signal received at the subscribers' side is of broad bandwidth, noise and beat interference tend to occur when a conventional CATV tuner is used, causing the received picture affected. The problem must be improved.